1. Field of the Invention
This invention relates to a solar cell module having a highly agreeable appearance and capable of storing a large volume of information relating to the solar cell module itself that is recorded on the light receiving surface.
2. Related Background Art
Firstly, a known popular solar cell module will be described by referring to FIGS. 4A and 4B of the accompanying drawings.
FIGS. 4A and 4B illustrate a known solar cell module. FIG. 4A is a schematic perspective view and FIG. 4B is a cross sectional view taken along line 4B--4B in FIG. 4A.
As seen from FIGS. 4A and 4B, the known solar cell module 300 comprises a host of photovoltaic elements 301 covered by a front surface member 303, a front surface sealing member 302, rear surface sealing members 304 and a rear surface member 306. In the case of the illustrated solar cell module, the rear surface member 306 is bored through at a pair of longitudinally and oppositely arranged positions to lead out respectively the positive electrode and the negative electrode, which are then connected to the respective terminal boxes 307, 308 and electric wires 309 in order to output electric power. The electric wires 309 are in turn connected to respective connectors 310, 311.
In the manufacturing process for such known solar cell modules 300, the date, the process, the rated values, the destination of shipment and other data identifying each module 300 or each batch of photovoltaic elements 301 are normally logged and controlled by using serial control (ID) numbers allocated to solar cell modules.
More specifically, such a known solar cell module 300 is typically provided with a display section 312 carrying a name plate thereon and arranged on the rear surface thereof. The ID number of the solar cell module 300 is carried on the name plate of the display section 312 in an attempt to raise the ratio of the area dedicated to the photovoltaic function of the module relative to the entire surface area of the light receiving front surface. The control number carried on the name plate of the display section 312 may take the form of a bar code.
Such a known solar cell module 300 can experience problems as identified below due to the arrangement of the name plate of the display section 312 carrying the control number thereon on the rear side of the solar cell module 300.
Firstly, when manufacturing solar cells 300, each solar cell module 300 has to be turned upside down when gluing a name plate to the display section 312 and inspecting the solar cell module 300. In this way the light receiving front surface member 303 of the solar cell module 300 can inadvertently be damaged thereby reducing the manufacturing yield.
Meanwhile, solar cell modules 300 can improve their photovoltaic effect when suitably arranged in array.
For example, a solar cell module array can be optimally designed to minimize the power loss on the basis of I-V curve data of the solar cell modules. Then, solar cell modules 300 will be arranged or combined according to the design before they are shipped.
However, on the site of installing the solar cell modules 300, they will have to be turned upside down once again in order to identify their respective control numbers if they cannot be identified by viewing the light receiving surfaces thereof. Then, if any of the solar cell modules 300 are seriously damaged in the process of being turned upside down and have to be replaced, a solar cell module array incorporating the replaced solar cell modules will have to be optically designed once again for array arrangement. It is very difficult to realize an optimal array design on site.
Additionally, when solar cell modules 300 are used outdoors for a prolonged period of time, the front surface members 303 of the solar cell modules 300 can become damaged by foreign objects that collide with the front surface members, particularly on windy days during storm seasons. The damaged solar cell modules 300 should be replaced. Hence, the type of damaged solar cell modules 300 and that of their connectors 310, 311 must be identified by viewing the display sections 312 of the damaged solar cell modules 300 and their replacements are brought in accordingly.
If the light receiving surfaces of the damaged solar cell modules 300 do not say anything about their types, then all the solar cell modules 300 from the top row down to the rows of the damaged solar cell modules 300 of the array will have to be removed to identify their respective control numbers. If the solar cell module array is arranged on a roof and such a cumbersome operation of identifying the control numbers must be carried out, then the replacement time for the solar cell modules 300 is enormous and the roof must remain partly dismantled during that time. Thus, it is highly desirable that solar cell modules 300 carry their respective control numbers and other data on the light receiving surfaces thereof, from a servicing point of view.
In an attempt to solve the above identified problems relating to arranging a display section on the light receiving surface of each solar cell module, the following proposals are known to date.
For example, Japanese Utility Model Publication No. 61-41261 describes a technique of arranging a cut-through pattern of characters and other symbols in the photoelectric conversion area of a solar battery and filling the cut-through pattern with an insulating material showing a desired color. In this way, the characters and the symbols of the pattern may be visibly displayed and recognized due to the color difference between the insulator and the semiconductor layer.
Japanese Utility Model Publication No. 5-38464 described a colored solar cell module. According to the patent document, a solar cell module is provided on the surface of the solar cells with a color filter adapted to transmit light with a wavelength band that contributes to the photovoltaic effect of the solar cell module and a color scattering layer for transmitting part of the light transmitted through the filter and irregularly scattering the remaining part of the light.
Japanese Utility Model Publication No. 6-27964 describes a technique of arranging solar cells and color scattering reflector panels into a mosaic so that characters and other symbols may be visibly displayed and recognized by means of the color scattering reflector panels of the mosaic.
Japanese Utility Model Publication No. 7-26849 describes a technique of arranging an identification pattern formed in a laminate of a transparent electrode, an amorphous silicon layer and a metal layer formed on an insulating substrate that transmit light in a solar battery.
Japanese Patent Application Laid-Open No. 8-204220 describes a technique of partly modifying the direction of reflection and the reflectivity of the photovoltaic layer of a solar battery by making it project an undulated profile and visually display a desired pattern.
Japanese Patent Application Laid-Open No. 9-97918 describes a technique of displaying characters and other symbols on the light receiving surface of a solar cell module by differentiating the surface contour of a coating member and of a neighboring area of the surface of the module.
However, the above listed known techniques are accompanied respectively by the following problems.
While the techniques as disclosed in Japanese Utility Model Publications Nos. 61-41262, 6-27964 and 5-38464 and Japanese Patent Applications Laid-Open Nos. 8-204220 and 9-97918 can minimize the reduction in the photovoltaic effect of a solar cell module and allow the characters and other symbols it carries to be clearly recognizable, the storable volume of information remains limited because information cannot be stored densely in a given area.
The technique as disclosed in Japanese Utility Model Publication No. 7-26849 takes away from the appearance of the solar cell module to which the technique is applied because an information carrying body is arranged on the light receiving surface of the solar cell module and carries a visible pattern of bar codes and/or some other data.
In short, with any of the above listed known techniques, an information carrying body is visibly placed on the light receiving surface of a solar cell module. None of the above patent documents discloses an information carrying body that carries information invisibly.
Additionally, no techniques are known to date that arrange an information carrying body on the light receiving surface of a solar cell module carrying data such as the electric characteristics of the product obtained on the basis of the I-V curve data of production, in addition to the date, the process, the rated values, the destination of shipment and other data for the product.